Grinding machine



J 2, 1953 c. J. GREEN 2,640,300

GRINDING MACHINE Filed Feb. 18, 1952 5 Sheets-Sheet l INVENTOR. Cum-Ne:J (flea-E Mum June 2, 1953 c. J. GREEN GRINDING MACHINE 5 Sheets-Sheet 2Filed Feb. 18, 1952 WEE INVENTOR.

LAW

m. w 6 J Q a m e M. 0

w. QM,

* Q Q Wm f NV June 2, .1953

Filed Feb. 18, 1952 C. J. GREEN GRINDING MACHINE 5 Sheets-Sheet 3INVENTOR.

WBLW

June 2, 1953 c. J. GREEN I 2,640,300

GRINDING MACHINE Filed Feb. 18, 1952 5 Sheets-Sheet 4 INVENTOR. Cum-Na:J Gena-N C. J. GREEN GRINDING MACHINE June 2, 1953 Filed Feb. 18, 1952 5Sheets-Sheet 5 v INVENTOR. "e44 CLARENCE J 6'KEEN BY M -wan.

Patented June 2, 1953 GRINDING MACHINE Clarence J. Green, Worcester,Mass, assignor to Norton Company, Worcester, Mass, 21 corporation ofMassachusetts Application February 18, 1952, Serial No. 272,202 (01.51--94) 7 Claims. 1

The invention relates to grinding machines and more particularly to amachine for grinding partial cylindrical surfaces.

One object of the invention is to provide a simple and thoroughlypractical grinding machine for grinding a partial cylindrical surface ona work piece. Another object is to provide a fluid motor actuated worksupport to oscillate a work holder to facilitate grinding a partialcylindrical surface on a work piece. Another object is to provide anelectrically controlled mechanism which is actuated by and in timedrelation with the rotary motion of the work support to control thedirection of movement of the work. Another object is to provide acontrol mechanism for the work oscillation motor which actuated by andin timed relation with the rapid approach and receding motion of thegrinding wheel. A further object is to provide an electrically actuatedhydraulically operated control valve for the work oscillation motorwhich is operated in timed relation with the wheel feed controllingmechanism. Other objects will be in part obvious or in part pointed outhereinafter.

The invention accordingly consists in the features of construction, andarrangements of parts, as will be exemplified in the structure to behereinafter described and the scope of the application of which will beindicated in the foregoin claims.

In the accompanying drawings, in which is shown one of variousembodiments of the mechanical features of this invention,

Fig. l is a front elevation of the improved grinding machine;

Fig. 2 is a cross sectional view, on an enlarged scale, through thegrinding wheel feeding mechanism;

Fig. 3 is a combined electrical and hydraulic diagram of the actuatingmechanism and of the control therefor;

Fig. 4 is a right hand end elevation, on an enlarged scale, takenapproximately on the line 4 l of Fig. l, partly in section to clarifythe illustration;

Fig. 5 is a staggered. horizontal sectional view, on an enlarged scale,taken approximately on the line t e of Fig. l, through the work drivinghead.

Fig. 6 is a fragmentary View on an enlarged scale showing the path ofoscillation of the work piece relative to the grinding wheel;

Tis an enlarged View, partly in section, of the work holder;

Fig. 8 is a left hand end elevation of the work holder as shown in Fig.7.

Fig. 9 is a right hand end elevation of the won: holder as shown in Fig.7; and

Fig. 10 is a cross sectional view, taken approximately on the linelt-lll of Fig. 7, through the work holder.

A grinding machine has been illustrated in the drawings comprising abase it which supports a longitudinally movable work table H. The tableH supports a swivel table H which in turn supports a rotatable worksupporting and driving mechanism to be hereinafter described. The tableIi is arranged to slide longitudinally on a 4-way l3 and a flat way H3formed on the upper portion of the base 10.

A manually operable table traverse mechanism is provided for traversingthe table I I longitudinally to facilitate positionizn a work piece tobe ground into operative relation with the grinding wheel to behereinafter described. This mechanism may comprise a rotatable handwheel Iii mounted on the outer end of a shaft H6. The shaft l6 supportsa gear I! which meshes with a; gear l8 supported on a rotatable shaftI9. The shaft I9 is provided with a gear 2i! which meshes with a rackbar 21 depending from the under side of the table H.

The base it also serves as a support for a transversely movable wheelslide 25 which is arranged to slide transversely on the usual fiat and-way (not shown) formed on the upper portion of the base H0. The wheelslide 25 supports a rotatable wheel spindle 2.6 in suitable bearing (notshown). The spindle 28 serves as a support for a grinding wheel 21. Asuitable driving mechanism is pro-- vided for rotating the wheel spindle26 and the grinding wheel 2'! comprises an electric motor 28' mounted onthe upper portion of the wheel slide 25. The motor 28 is provided with amultiple V-grooved pulley 29 which is connected by multiple V-bolts towith a multiple V-grooved pulley 31 mounted on the right hand end of thewheel spindle 26 (Fig. 1)..

A suitable feedin mechanism is provided for feeding the grinding wheelslide 25 and the grinding wheel 2'! transversely. This mechanism maycomprise a rotatable feed screw 32. A feed nut 33 meshes with a feedscrew 32 which is supportedon spaced anti-friction bearings 34 which arein turn supported by a housing 35 fixedly mounted on the under side ofthe wheel slide 25. The feed screw 32' is provided with a reducedcylinder end portion 36 which is slidably keyed within a rotatablesleeve 3'l. The sleeve 3'3 is journalled. in bearings 38 to form arotatable support for the left hand end of the feed screw 32 (Fig. 2).The

right hand end of the feed screw 32 is supported on an anti-frictionbearing 39 carried by a slidably mounted sleeve 40. The left hand end ofa rotatable shaft 42 is journalled on bearings 43 and the right hand endthereof is slidably keyed within the sleeve 37. A gear 44 is mounted onthe left hand end of the shaft 42 and meshes with a gear 45 which isconnected to rotate with a feed wheel 46. The feed wheel 46 is providedwith a micrometer set adjusting mechanism 41. A pivotally mounted stoppawl 48 is supported on a stud 49 on the front end of the machine base0. The pawl 48 is arranged to be engaged by a stop abutment (not shown)on the feed wheel 46 to limit the infeeding movement of the grindingwheel. It will be readily apparent from the foregoing disclosure that arotary motion of the hand wheel 46 will be imparted through themechanism just described to cause a rotary motion of the feed screw 32and a transverse feeding of the wheel slide 25. The direction ofrotation of the feed wheel 45 serving to determine the direction ofmovement of the wheel slide 25.

A rapid positioning mechanism is provided for rapidly moving the wheelslide 25 and the grinding wheel 21 to and from an operative position.This mechanism is preferably a hydraulically operated mechanismcomprising a cylinder 50 which is fixedly supported relative to the base[0. The cylinder 50 contains a slidably mounted piston 51 which isconnected to one end of a piston rod 52. The other end of the piston rod52 is connected to the slidably mounted sleeve 40. It will be readilyapparent from the foregoing disclosure that movement of the piston iwithin the cylinder 55 will impart an axial movement to the feed screw32 to cause a rapid traverse of the wheel slide 25.

A control valve 53 is provided for controlling the admission to andexhaust of fluid from the cylinder 50. The valve 53 is preferably apiston type valve comprising a valve stem 54 having a plurality of valvepistons 55, 56, 57, and 58 formed integrally therewith. A compressionspring 59 is provided normally to maintain the valve stem 54 in a righthand end position with the valve pistons 55, 56, 51, and 58 positionedas illustrated in Fig. 3. A solenoid S! is provided which when energizedserves to shift the valve stem toward the left (Figs. 2 and 3) toposition the valve pistons 55, 56, 51, and 58 so as to cause a rapidapproaching movement of the wheel slide 25.

- -A fluid pressure system is provided for supplying fluid underpressure comprising a motor driven fluid pump 65 which draws fluid froma suitable source of supply and forces fluid under pressure through apipe 55 to the control valve 53. Fluid under pressure in the pipe 55enters a valve chamber 5'! formed between the valve pistons 55 and 5Band passes through a passage 68 into a cylinder chamber 59 to cause thepiston 55 to move towards the right (Figs. 2 and 3). During thismovement of the piston 5i fluid within a cylinder chamber may exhaustthrough a passage H, through a valve chamber 12 and out through anexhaust pipe 73. Movement of the piston 5! toward the right serves tocause the wheel slide and the grinding wheel 21 to move rearwardly to aninoperative position.

When it is desired to cause a rapid approaching movement of the wheelsleeve 25 and the grinding wheel 21, the solenoid Si is energized toshift the valve stem 54 toward the left so that fluid under pressurefrom the pipe 66 enters the valve chamber 12 and passes through thepassage H into the cylinder chamber 10 so as to cause the piston 5! tomove toward the left thereby applying a rapid approaching movement tothe wheel slide 25 and the grinding wheel 21. During this approachingmovement fluid within the valve chamber 69 may exhaust through a passage58 into the valve chamber 51 and exhaust through a pipe '14.

It is desirable to slow down the rapid approaching movement of thepiston 5! before it reaches the end of its movement toward the left.This is accomplished by providing two ports 55a and 58b. The port 5811allows substantially unrestricted exhaust of fluid through the passage68. As the piston 5! starts its movement toward the left, fiuid mayexhaust through the port 68a and also through the port 881) through athrottle valve 550 and a pipe 68d through the passage 53 to control therapid approaching movement of the wheel slide 25 and the grinding wheel21. During the movement of the piston 5! toward the left, the piston 51covers the port 63a before it reaches the end of its stroke after whichfluid within the cylinder chamber must exhaust through the port 6819 andthrough the throttle valve 58c which is set to slow down the rapidapproaching movement of the piston 51 before it reaches the end of itsstroke. -A ball check valve 58c is provided between the pipe 68d and theport 68b which is arranged to allow substantially unrestricted flow offluid into the cylinder chamber 59 when the control valve 53 isreversed.

It is similarly desirable to cushion the rear-- ward movement of thepiston 51 when the grinding wheel 27 and the wheel slide 25 are movedrapidly to a rearward or inoperative position. This is preferablyaccomplished by the right hand end of the piston rod 52 engaging a dashpot piston 14. The dash pot piston M is slidably mounted within the dashpot 15. During the rearward movement of the piston 51, that is, towardthe right (Fig. 3), a rapid movement is obtained due to free exhaust ofthe fluid through the passage H until the right hand end of the pistonrod 52 engages the dash pot piston I4. When the piston rod 52 moves intoengagement with the dash pot piston 74, continued movement of the pistonis slowed down by fluid within a dash pot chamber 76 which may exhaustthrough a passage 71, through a throttle valve 78 into the passage H.The rate of slow-down movement of the piston 5i is determined by thesetting of the throttle valve 78. valve '29 is provided between thepassage TI and the passage H to facilitate allowing an unrestricted flowof fluid into the dash pot chamber l6 when the approaching movement ofthe piston 65 is started in order to facilitate resetting the dash potpiston i l. The mechanism just described serves to control the rapidapproaching and receding movement of the wheel slide 25 and the grindingwheel 2?.

A feeding mechanism is provided for controlling the feed of the wheelslide 25. This mechanism may comprise a fluid motor including a cylinder86. The cylinder 86 contains a slidably mounted piston 8! having a rackformed on its upper surface. The rack 88 meshes with a gear 89 mountedon a shaft 98. The shaft 90 also carries a gear 91 which meshes with thegear 44. =Fluid under pressure may be passed either through a pipe 92 ora pipe 93 to opposite ends of the cylinder 85 to cause the endwisemotion A ball check of the piston 81 which is transmittedthroughthe gearmechanism above described to impart a ro tary motion to the feed screw32 to feed thewheel slide 25 and the grinding wheel 2'! either toward orfrom the work piece being ground.

A feed control valve 9 1 is provided for controlling the admission toand exhaust of fluid from the cylinder 85. The feed control valve 94! isa shuttle-type valve comprising a valve stem 95 having a plurality ofspaced valve pistons 96, 91, and 98 formed integrally therewith. Asshown in Fig. 3, a pipe 99 conveysfluid under pressure from the pressurepipe 66, through a pipe me into a valve chamber formed between the valvepistons 91 and 9B. Fluid entering the valve chamber passes through thepipe 93 into the cylinder chamber formed at the right hand end of thecylinder 86 to cause the piston 81 to move toward the left therebyrotating the feed screw 32 so as to cause a rearward movement of thegrinding wheel 21 and the wheel slide 25. During movement of the piston81 toward the left, fluid may exhaust from the left hand end chamber ofthe cylinder 86 through the pipe 92, through a. valve chamber formedbetween the valve pistons B6 and 9'! and passed out through a pipe H3and exhaust through a selector valve IM to be hereinafter described.

The shifting movement of the feed control valve 94 is preferablycontrolled in a timed relation with movement of the control valve 53'. Apipe IBI conncets the valve 53 with an end chamber formed at the righthand end of the valve 94. Similarly a pipe m2 connects the control valve53 with an end chamber formed at the left hand end of the valve 91% Inthe position of the valve 53 (Fig. 3), fluid under pressure enters thevalve chamber '67 passes through the passage =68 causes the rapidrearward movement of the piston 5| and also passes through the pipe IEIIto cause the feed control valve stem 85 to move toward the left into theposition illustrated in Fig. 3. In this position as above described,fluid passes through the pipe 93 into a cylinder chamber at the righthand end of the cylinder 85 to cause the piston 37 to move toward theleft to cause a rearward movement of the wheel slide '25.

When the solenoid SI is energized to initiate a feeding cycle, the valvestem 55 is moved toward the left (Fig. 3) so that fluid under pressurefrom the pipe 6-6 enters the valvev chamber I2 and passes through thepassage TI into the cylinder chamber Hi to cause rapid movement of thepiston 5! toward the left. At the same time fluid passes through thepipe IE2 into the valve cham-- her at the left hand end of the valve 94toshift the valve stem 95 toward the right. In this position, fluidunder pressure from the pipe I passes through the valve chamber formedbetween the valve pistons 96 and 97 and passes through the pipe 82 intothe cylinder chamber formed at the left hand end of the cylinder 85 soas to cause the piston 8! to move toward the right. During the movementof the piston Ill toward the right, the feed screw 32 is rotated in theopposite direction to impart an infeeding movement to the grinding wheel21' and the wheel slide 25.

The selector valve M4 is a rotary-type valve which serves to render thegrinding feeding mechanism manual or automatic as desired. The selectorvalve HM is shown diagrammatically in Fig. 3 in which the valve rotor isprovided with a central passage I and a plurality of spaced 6 radiallyextending passages I 96, I111, I08 and I091.

Armanually operable control lever IIll'is providedfor actuating theselector valve H34. As. shown in Fig. 3 the selector valve I04 is in aposition to produce an automatic actuation of the piston 81 in timedrelation with movement of the piston 5!. A pair of pipes III and H2 areconnected between the feed control valve 94 and the selector valve I04.When valve MM is turned to a manual position, with lever II!) inposition 0a;

fluid under pressure may pass through the passage !06 and be conveyed tooppositeends of the A pipe H3 is connected between cylinder 86. the feedcontrol valve 94 and the selector valve HM and as shown in Fig. 3 isarranged to exhaust fluid from the valve chamber located between thevalve pistons Miami 91, through the passage H18 in the selector valve194, through thecentral passage Hi5, through the passage I91 and intoanexhaust pipe I15. A pipe H4 is connected between the pipe Iilt and theselector valve I84 and is arranged so that when the selector valve I04-is turned to a manual position fluid under pressure from the pipe 99 andthe pipe I90 may pass through the pipe II through-a transversepassageI07, through the central passage I05 from which it is passed to bothends of the cylinder 86.

Fluid under pressurefrom the central passage H35 in the selector valveN14 is also conveyed through a pipe it? to a fluid control cylinder l 20for actuating a normally open spaced limit switch LS1. The cylinder I20contains a pair of slidable pistons IZi and I23. The piston I21 isprovidedwith a piston rod I22 which isnormally urged in a right handdirection by a compression spring I28. When fluid under pressure ispassed through a pipe I24 into a cylinder chamber I25 .or through pipe I2.! into a cylinder chamber I 26, the

piston rod I22 will be moved toward the left.-

(Fig. 3) to actuate the limit switch LSI which serves to start themotion of the work driving motor in a manner to be hereinafterdescribed.

The swivel table I2 serves as a support for a rotary work supportcomprising a head stock 35 and a foot stock I36 which are provided withwork supporting centers I3! and I38, respectively. The work centers I3!and I38 are arranged to rotata-bly support "a work holder 33!) whichwill be more fully described hereinafter.

The head stock I comprises a rotatable spindle Hill which is journalledin spaced anti-friction bearings Isl, M2, and I43 (Fig. 5). The lefthand end of the spindle I is providedwith. a sprocket M which isconnected by a cog belt 145 with asprocket l l tmounted on a rotatableshaft Ml. The cog belt I45 is a standard. well known belt. such as forexample a timing belt manufactuned by the L. H; Gilmer-Company. Theshaft MT is supported by spaced anti-friction bearings M8 and I 49carried by the head stock I.35., A crank arm I59 mounted on the righthand end of the shaft hi! and serves when oscillated to transmit anoscillating movement to the head stock spindle Edd and also to the workholder I39.

A fluid motor i5! is provided for imparting an oscillating movement tothe crank arm I50. The motor comprises a fluid pressure cylinder I52having a slida'bly mounted piston I53 therein. The piston I53 isconnected to a double end piss ton rod I 54 (Figs. 3 and 4). A. yokedmember I55 is mounted on the left hand end of the pis ton rod I 54 andis connected by a stud 55. with a link 55?' The link I5! is connected bya stud I-fifi with the crank arm Hit. It will be readily apparent fromthe foregoing disclosure that when fluid is passed alternately toopposite ends of the cylinder I52 to cause a reciprocatory movement ofthe piston I53, an oscillating motion will be imparted through themechanism just described to impart an oscillating movement to the workholder I39 to facilitate grinding a partial cylindrical surface on awork piece being ground. Fluid under pressure from a reversing valve tobe hereinafter described is passed through a pipe I69 or a pipe I'6I toopposite ends of the cylinder I52.

It is desirable to slow-down the movement of the piston I53 beforereversal. This is preferably accomplished by providing a normallyoperative throttle valve at each end of the cylinder to restrictadmission to end exhaust of fluid from the opposite entrance of thecylinder I52 as the piston I53 approaches the end of its reciprocatorystroke. As illustrated in Figs. 3 and 4, a piston type valve is providedcomprising a valve stem I62 having spaced valve pistons I63 and I64formed integrally therewith forming a valve chamber I65 and between.When fluid under pressure passes through the pipe I62 into the valvechamber I65, it passes through a passage I66 into a cylinder chamber I69to cause the piston I53 to move toward the right (Figs. 3 and 4) Anadjustable throttle valve I98 is provided so that when the valve stemI62 is moved toward the right and the valve piston I63 covers thepassage I66, fluid may pass through a' port I61, through the throttlevalve I68 into the cylinder chamber I69 to start movement of the pistonI53 toward the right.

A similar valve is provided at the other end of the cylinder I52comprising a valve stem I12 having spaced valve pistons I13 and I14formed integrally therewith forming a valve chamber I15 therebetween.When fluid under pressure is passed through the pipe I6l into the valvechamber I15, it may pass either through a passage I16 or through a portI11 depending upon the position of the valve pistons I13 and I14. Asillustrated in Fig. 3, fluid under pressure entering the valve chamberI15 passes through the port I11 and through a throttle valve I18 intothe passage I16 andinto the cylinder chamber I11.

The valves I62 and I12 are preferably controlled by and in timedrelation with the movement of the piston I53. The piston rod I54 carriesa pair of adjustable dogs I8I and I82 which are arranged to move intoengagement with valve stems I62 and I12 respectively. It will be readilyapparent from the foregoing disclosure that when the piston I53 isreciprocatory within cylinder I52, the dogs I8I and I82 willsuccessively engage and actuate the valves I62 and I12 respectively. Asshown in Fig. 3 fluid under pressure passing through the pipe I60,through the valve chamber I65, through the passage I66 into the cylinderchamber I69 starts movement of the piston I53 toward the right. Fluidwithin the cylinder chamber I19 may exhaust through the passage I16,through the throttle valve I18, through the port I11, through the valvechamber I15 and out through the pipe I6I. It will be readily apparentfrom this arrangement that the initial movement of the "piston I53toward the right will be at a slow rate controlled by the setting of thethrottle valve I18. As the piston rod I54 moves toward the right, thereleased compression of a spring I86 serves to move the valve stem I12toward the right so as to open the passage I16 directly to the valvechamber I15 so that unrestricted exhaust or fluid from the cylinderchamber I19 may be obtained in order to 6 facilitate movement ofthe'piston' at a normal rate. The piston I53 continues its movementtoward the right (Fig. 4) at a normal rate until the dog I8I engages thevalve stem I62 and moves it toward the right to cut oil the passage offluid through the passage I66. The flow of fluid under pressure from thepipe I60 into. the valve chamber I65 thereafter passes through the portI61 and through the throttle valve I68 so as to cut down the passage offluid into the cylinder chamber I69 and thereby to slow-down the rate ofmovement of the piston I53 as it approaches the right-hand end of itsstroke. By the provision of the slow-down valve above described, aslowing-down movement of the piston I53 is obtained before reversal ateach end of the stroke of the piston I53 and a slow starting of thepiston inthe reverse direction is also obtained. It will thus beapparent that deceleration and acceleration of the piston movement isobtained at each end of its stroke;

A suitable reversing mechanism is provided for controlling the admissionto an exhaust or fluid from the fluid motor I5I. This mechanism maycomprise a solenoid actuated reversing valve I comprising a valve stemI66 having a pair of spaced valve pistons I81 and I88 formed integrallytherewith. A pressure pipe I89 conveys fluid under pressure to a valvechamber I90 located between the valve pistons I81 and I89. In theposition illustrated in Fig. 2, fluid entering the valve chamber I96 maypass through the pipe I66 into the cylinder chamber I69. In thisposition of the valve, fluid exhausting through the pipe IBI passesthrough a valve chamber I9I and out through an exhausting pipe I92.

A pair of solenoids S3 and S4 are provided at opposite ends of the valveI85 for shifting the valve stem I86 endwise so as to reverse the flow offluid to the fluid motor I5I. As illustrated in Fig. 3, solenoid S6 isshown energized so that the valve stem I86 is in its left hand end ofposition. When solenoid S3 is energized, the valve stem I86 is shiftedtoward the right so that fluid under pressure in the valve chamber I98may pass through the pipe I6I in the cylinder chamber I19 to cause thepiston I53 to move toward the left. During this movement fluidexhausting from the cylinder chamber I69 passes through the pipe I 69,through a valve chamber I93 and out through the exhaust pipe I92.

It is desirable to provide a suitable control mechanism so' that thefluid motor I5I may be started and stopped automatically in timedrelation with the other mechanisms of the machine. This is preferablyaccomplished by a solenoid actuated start-stop valve I95 which comprisesa valve stem I96 having a plurality of spaced valve pistons I91, I98 andI99 formed integrally therewith. The valve pistons I91, I98, and I99form a series of valve chambers 2'96 and 2M. A compression spring 282serves normally to hold the valve stem 96 in its left hand end position.A solenoid S2 is provided which when energized serves to shift the valvestem I96 toward the right so that the fluid under pressure from thepressure pipe 99 may pass into the valve chamber 296 and through thepipe I89 to the reversing valve I85. It will be readily apparent fromthe foregoing disclosure that by timing the energization of the solenoidS2, the fluid motor I5I may be started and stopped automatically in amanner to be hereinafter described.

An electrically operated control mechanism is provided for adj ustablycontrolling the extent of 9 oscillation of the headstock spindle I40.This mechanism may comprise a plate 205 which is fixedly mounted on theright hand end of the spindle I40 (Fig. The plate 205 is provided withan annular T-slot 206 which supports a pair of adjustable reversing dogsand 208. Clamping screws are provided for clamping the dogs 20] and 208in the desired adjusted posi tion. The dogs 20? and 268 are providedwith adjustable actuating screws 209 and 2m which are arranged to engageactuating rollers ZI I and '2I2 of a pairof limit switches LS2 and LS3pair of adjustably mounted stop screws 2m and 2 which are arranged to beengaged by stop abutments 2E8 and 2H3 formed on the'dogs 253i and 208respectively. It will be readily apparent from the foregoing disclosurethat actuation of the limit switches LS2 and LS3 will cause a; shiftingmovement of the reversing valve I65 to change the direction ofoscillation of the spindle Hit and the stop screws 2H5 and an andthereafter function positively to stop the movement of the spindle ineither direction.

The work holder I39 is arranged to support a jet motor blade 225 havingan end. portion 226 (Fig. 7) which is provided with a hole 221. Theother end of the blade 225 to be ground is provided with a boss 223which engages a V-shaped notch 229 formed in a portion of the workholder I39. The left hand end of the blade 225 engages a locatingsurface 230 formed on the holder I 39 and serves to locate the left handend of the blade. A slidably mounted locating stud 231 is provided withan actuating knob 232 and 'is arranged to be moved into engagement withthe hole 227 precisely to locate the blade 225 for a grinding operation.A clamping screw 233 is provided adjacent to the left hand end of thework holder I39 to facilitate clamping the left hand end of the blade inposition. A spring pressed ball 235 is provided on the work holder E39and is arranged to engage V-shaped groove 236 on .the stud 23! tomaintain the stud in an operative position. A clamping screw 2334- isprovided adjacent to the right hand end of the work holder I39 tofacilitate clamping the boss 228 in engagement with the v-shaped notch229.. As

previously explained the work holder I39 after being loaded is supportedby the headstock center I37- andthe foot stock center I38.

In order to facilitate driving the work holder I39 an adjustably mountedwork driving dog 23? is clamped on a boss 233 on the left hand-end ofthe" work holder I39. The driving dog 23? is provided with apair ofspaced projecting arms 239 and 249 each of which is provided with' 2418and also to energize the solenoid SI.

broken line posiiton' 225a (Fig. 6). Soas to grind a partial cylindricalsurface 244 on the blade 225.

In order to control the cycle of operation, a manually operated cyclecontrol lever 245 is pivctally mounted on the front of the machine baseIll. The control lever M5 is arranged to actuate a start switch 2:38 anda stop switch 241. A manually operative switch 249: is connected betweenthe limit switch LSI and a relay switch CRI. When the switch 249 isclosed, the relay switch CRI may be controlled by the cycle controllever 2%. If the switch 239 is opened, a manual control of the workoscillation may be obtained by manually closing a push button switch 2%.v

Assuming the switch 249 to be closed, a grinding cycle may be started bymanually rocking the cycle control lever 245 in a clockwise direction(Fig. 3) to close the start switch 246. Closing switch 25% serves toenergize an electric timer The timer 2E8 is'operatively connected tocontrol the duration of the grinding cycle. When the sole noid SI isenergized, the valve 53 is shifted toward the left so that fluid underpressure is passed through the pipe IilI into the cylinder chamber I25to move the piston I2I toward the left so as to actuate the limit switchLSI. The closing of the limit switch LSI serves to energize the relayswitch CRI which closes a circuit to energize the solenoid S2 therebyshifting the startstop valve Illa to pass fluid under pressure to thefluid motor I5i thereby starting oscillation of the headstock spindleMI}. During the shifting movement of the valve 53 toward the left fluidfirst passes through the pipe I02 after which fluid under pressure ispassed through the passage lI into the cylinder chamber ill to cause arapid movement of the piston 5| toward the left to produce a rapidapproaching movement of the wheel slide 25 and the grinding wheel 21.

As previously explained passage of fluid through the pipe I 62 serves toshift the'feed control valve Q4 so as to admit fluid under pressure tothe feed motor thereby starting movement of the piston 81 toward theright to impart .a rotary motion to the feed screw 32 to advance thewheel slide 25 and the grinding wheel 21 at a rate suitable forcontrolling the grinding operation on the work piece being ground. Thefeeding movement of the wheel slide 25 and the grinding wheel 2? willcontinue until a predatermined time interval has elapsed at which timethe timer 248 will open a circuit thereby de energizing the solenoid SIso that the released compression of the spring 59 will shift the valve53 toward the right into the position illustrated in Fig. 3. When thevalve 53 moves into this position, fluid will be exhausted from thecylinder chamber I 25 thereby releasing the compres sion of the springI28 to allow the limit switch LSI to open thereby deenergizing relayswitch CRI to deenergize the solenoid S2 thereby cutting-01f the flow offluid under pressure to the fluid motor I 5| to stop the oscillation ofthe work holder I39 and the headstock spindle I 40. At the same time,the valve 53 will pass fluid under pressure through the passage 68 tocause a rapid rearward movement of the piston 5i which causes the wheelslide 25 and the grinding wheel 21 to move rearwardly to an inoperativeposition. When the control valve 53 reaches the position illustrated inFig. S-fluid under pressure is passed through the pipe IIlI .to shiftthefeed control valve 94. toward the left thereby reversing the flow offluid to the feed motor 85 to cause the piston 8'! to move toward theleft into the position illustrated in Fig. 3. This movement of thepiston 81 serves to rotate the feed screw 32 in the reversing directionto reset the feed mechanism for the next grinding operation.

The machine has been illustrated as set up for grinding asemi-cylindrical surface 244 on a blade 225 while the blade is swung, anangle A (Fig. 6) has control by the setting of the dogs and 238. It willbe readily apparent that by adjusting the position of the dogs 20'] and268 relative to the blade 205, arcuate surfaces of varying lengths maybe readily ground.

The operation of this improved grinding machine will be readily apparentfrom the foregoing disclosure assuming all of the mechanisms to havebeen previously adjusted, a work piece 225 is mounted in position in thework holder I39 as above described. The work holder i39 is thenpositioned in the machine and is supported by the headstock center 13'!and the footstock center I38. The control lever 2&5 may then be rockedin a clockwise direction (Fig. 3) to close the start switch 245 whichserves to start a grinding cycle. The closing of the start switch 245energizes the solenoid Si and at the same time energizes the timer 248.Energizing the solenoid SI shifts the control valve 53 to pass fluidthrough the pipe I02 into the cylinder chamber 125 to close the limitswitch LSI thereby starting the fluid motor 15! and the oscillation ofthe headstock spindle I 10. At the same time fluid passes through thepassage 7| into cylinder chamber ill to keep a rapid approachingmovement of the grinding wheel 21 and the wheel slide 25. When fluidunder pressure is passed through the pipe Hi2 into the cylinder chamberl25, it is also conveyed to the feed control valve 194 to shift thevalve stem 95 toward the right (Fig. 3) to start movement of the saidpiston 8'! toward the right thereby imparting a rotary motion to thefeed screw 32 to feed the grinding wheel 21 toward the axis of the workpiece being ground to grinding semi-cylindrical surface 244 thereon. Theinfeeding movement, as caused by movement of the piston 81 toward theright, continues until the stop abutment on the feed wheel 46 engagesthe stop pawl 48. The grinding wheel 21 remains in grinding contact withthe work piece 225 until the timer 248 times-out thereby breaking acircuit to deenergize the solenoid Si. Deenergizing the solenoid SIreturns the valve 53 into the position illustrated in Fig. 3 therebystopping oscillation of the headstock spindle I40, rapidly moving thepiston 51 to a rearward or inoperative position, and also for moving thepiston 81 toward the left to reset the 'feeding mechanism for the nextgrinding cycle. If any time during a grinding cycle, if desired, thecycle may be stopped by rocking the control 245 in a counterclockwisedirection to open the stop switch 241 thereby interrupting the timecycle and returning the various mechanisms to the initial positions asin Fig. 3.

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany possible embodiments may be made of the above invention and as manychanges might be made in the embodiment above set forth, it is therebyunderstood that all matter hereinoeforeset forth or shown in theaccompanying drawingsis to be interpreted as illustrative and not in alimiting sense.

I claim:

1. In a grinding machine having a transversely movable rotatablegrinding wheel, means to feed the wheel transversely to produce agrinding feed, a longitudinally movable table, means to traverse saidtable longitudinally, a rotatable work support including a head stockand a foot stock center rotatably to support a work piece on said table,a work driving mechanism including a fluid motor arranged to oscillate awork piece continuously through a partial rotation, a reversing valvefor controlling the fluid motor. and means actuated by and in timedrelation with the rotary motion of the head stock spindle to control thereversing valve and thereby to control the extent of oscillation of thespindle.

2. In a grinding machine, as claimed in claim 1, in combination with theparts and features therein specified in which a pair of limit switchesare provided to actuate the reversing valve, and a pair of adjustabledogs carried by the headstock spindle for actuating the limit switchesto control the extent of oscillation of the fluid motor.

3. In a grinding machine having a transversely movable rotatablegrinding wheel, means including a fluid motor to cause a rapidapproaching and receding movement of said wheel, means including a fluidmotor to feed the wheel transversely to produce a grinding feed, arotatable work support including a rotatable headstock spindle and arootstock, a work driving mechanism including a fluid motor to oscillatethe spindle continuously through a partial rotation to facilitategrinding a partial cylindrical surface on a work piece, and meansincluding a control valve for controlling all of said, fluid motors soas to control the rapid approaching and receding and the grinding feedof said Wheel and the oscillation of the headstock spindle.

4. In a grinding machine, as claimed in claim 3, in combination with theparts and features therein specified of a solenoid-actuated reversingvalve to control the fluid motor, a pair of limit switches actuated byand in timed relation with the oscillation of the headstock spindle tocontrol said valve so as to control the extent of oscillation spindle, asolenoid-actuated control valve to control the admission of fluid underpressure to said reversing valve, a limit switch to control said lattervalve, and fluid actuated means operated by and in timed relation withthe feed control valve to start the fluid motor and thereafter to starta rapid approaching movement of the grinding wheel.

5. In a grinding machine, as claimed in claim 3, in combination with theparts and features therein specified of a solenoid-actuated reversingvalve to control said fluid motor, a pair of limit switches foractuating said reversing valve, adjustable dogs carried by said spindlewhich are arranged to actuate said limit switches so as to control theextent of the oscillatory stroke of the said spindle, asolenoid-actuated control valve to control the admission of fluid underpressure to said reversing valve, a limit switch operatively connectedto actuate said latter valve, a piston and cylinder to actuate saidlimit switch, and fluid connections between said cylinder and the saidcontrol valve which are arranged to start oscillation of the headstockspindle and thereafter to cause a rapid approach movement of thegrinding wheel.

6. In a grinding machine having a transversely movable rotatablegrinding wheel, means including a fluid motor to cause a transversefeeding movement of the grinding wheel in either direction, asolenoid-actuated control valve therefor, a rotatable work supportincluding a headstock spindle means including a fluid motor to oscillatesaid spindle, a control valve therefor to reverse the direction of saidmotor, means including adjustable dogs rotatable with said spindle tocontrol actuation of said control valve, a solenoidactuated controlvalve to control admission of fluid under pressure to said controlvalve, and a limit switch actuated by and in timed relation with saidfirst solenoid-actuated valve to energize the second solenoid-actuatedcontrol valve so as to start oscillation of the spindle before theforward movement of the grinding wheel is started.

'7. In a grinding machine having a transversely movable rotatablegrinding wheel, means to feed the wheel transversely to produce agrinding feed, a longitudinally movable table, means to traverse saidtable longitudinally, a rotatable work support on said table including arotatable headstock spindle, a fluid motor including a piston andcylinder operatively connected to oscillate the head stock spindlecontinuously through a partial rotation, a reversing valve therefor, anindependent l 4 valve for controlling the admission to and exhaust fromeach end of said cylinder, a passage between said valve and the ends ofsaid cylinder to allow unrestricted passage of fluid, an auxiliarypassage having a throttle valve therein between each of said valves andthe ends of said cylinder, adjustable dogs movable with said piston toactuate said valves to slow down the movement of the piston before itreaches the end of its stroke, and adjustable dogs positively to limitthe oscillatory stroke of said spindle in either direction, saidthrottle valve serving to slow down movement of the piston before thestop screws are engaged by said dogs.

CLARENCE J. GREEN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 730,445 Echols June 9, 1903 1,515,568 Fleming et al Nov. 11,1924 1,873,224 Shippy et a1 Aug. 23, 1932 2,077,359 Flygare Apr. 13,1937 2,247,228 Flygare June 24, 1941 2,427,283 Hopkins et al Sept. 9,1947

